Hi. A good friend of mine is trying to sell me an ASP .91 2-stroke engine. It's got the "Red" engine cylinder head. It appears to have very little flight time or engine running time on it.

Can you guys/gals tell me how good of an engine this is? Would you recommend another brand that is better? Any info on this engine would be wonderful and well appreciated. Thank you.
Clint

Good engine, not as powerfull as todays .91's and a bit heavier, but very reliable. Just keep the nitro at 5% or less.

Why that low? Thanks.
Clint

It needs to be that low because it has a very high compression ratio. Any higher and the nitro detonates and the engine will run real hot, then flame out. I think it was made for overseas where low nitro fuel is more common. However it gets good power on cheaper fuel. Not exactly a slouch on power, but not quite as good as a modern .91, but it does burn less fuel. Great for a tail heavy .60 sport plane. Doesn't burn much more fuel than a .60 and gobs more power. Also this is an ABC engine most modern .91's are ringed.

He says he wants $85 for the engine. Would you recommend just going to a Magnum .91 or SuperTigre .91? Let me know. I do appreciate all you help.
Clint

Clint, it is probably a good deal at $85. I have two 108s and they are decent. If money is not important, the new Magnum gets good reports, and I have an earlier version Magnum 91 that is a sweetheart.

BTW, ever hear of Burdett, Ks? I was born and raised there....

Clair Sieverling

Would you be interested in getting rid of that old .91 2-stroke? Let me know. I'd be willing to pay between $75-$85 or lower. Thanks.
Clint

The ASP Redhead is basicaly the same engine as the early Magnum, but with a higher compression head. If finding low nitro fuel is a problem you could always shim it up with extra head gaskets, or even replacing the head with a Magnum head.

In addition to lowering the nitro or reducing the compression on this engine, many people have better luck tuning the engine with an aftermarket carb.

Mine runs good but seems to prefer a 13x6 prop over the 14x6 prop I intended to run in my engine.

Thanks for the info. I think I'll just buy a Magnum .91 2-stroke. Thanks.
Clint

Not required. The stock carb works just fine. Works just like a SuperTiger carb.

Looks like we scared him off. Unless he wanted more power, or cannot get lower nitro fuel, $85 for this engine is money worth spending. One of the most reliable engines I have stock with no mods. Turns a 13-6 at almost 12,000 RPM and a 14-6 just over 11,000, and 5% fuel is cheap, even if I have to special order a case of it. It will run 10% in the winter.

he he he.

No, you guys didn't scare me off. I decided to go with a Magnum XL .91 2-stroke that I found here on RCU real cheap NIB. I like and trust Magnum and O.S., but O.S. engines are quite expensive. But if I were going to buy a good .91 2-stroke, I'd want one that would run perfect right outa the box. Thanks for all the info.
Clint

In regard to "Sport_Pilot", it is hard to find 5% nitro fuel here in Hays, KS and I was wanting the power and speed that a .91 2-stroke would provide me with on my bipe.